One caution based on my experience, if your purpose only involves date then be careful to include the timestamp. For example, say today is "2016-11-09". Comparison involving timestamp will nullify the logic here. Example,
// input
$var = "2016-11-09 00:00:00.0";
// check if date is today or in the future
if ( time() <= strtotime($var) )
{
// This seems right, but if it's ONLY date you are after
// then the code might treat $var as past depending on
// the time.
}
The code above seems right, but if it's ONLY the date you want to compare, then, the above code is not the right logic. Why? Because, time() and strtotime() will provide include timestamp. That is, even though both dates fall on the same day, but difference in time will matter. Consider the example below:
// plain date string
$input = "2016-11-09";
Because the input is plain date string, using strtotime() on $input will assume that it's the midnight of 2016-11-09. So, running time() anytime after midnight will always treat $input as past, even though they are on the same day.
To fix this, you can simply code, like this:
if (date("Y-m-d") <= $input)
{
echo "Input date is equal to or greater than today.";
}